package com.example.sisko_database;


import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseInit extends SQLiteOpenHelper {

	private static String DB_PATH = "";
	private static final String DB_NAME = "whatseat_db.sqlite";
	private final Context myContext;
	private SQLiteDatabase myDataBase;
	
	public DatabaseInit(Context context) {
		
		 super(context, DB_NAME, null, 1);
		 DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
		 this.myContext = context;
	}
	
	public void createDataBase() throws IOException{
		 
		boolean dbExist = checkDataBase();
		  
		if(dbExist){
			//do nothing - database already exist
		}else{
		  
			 //By calling this method and empty database will be created into the default system path
			 //of your application so we are gonna be able to overwrite that database with our database.
			this.getReadableDatabase();
		  
			try {
		  
				copyDataBase();
		  
			} catch (IOException e) {
		  
				throw new Error("Error copying database");
		 
			}
		}
		  
	}
		  
		 /**
		   * Check if the database already exist to avoid re-copying the file each time you open the application.
		   * @return true if it exists, false if it doesn't
		   */
	private boolean checkDataBase(){
	  
		File dbFile = new File(DB_PATH + DB_NAME);
        
		return dbFile.exists();
		
	}
		  
		 /**
		   * Copies your database from your local assets-folder to the just created empty database in the
		   * system folder, from where it can be accessed and handled.
		   * This is done by transfering bytestream.
		   * */
	 private void copyDataBase() throws IOException{
	  
		 //Open your local db as the input stream
		 InputStream myInput = myContext.getAssets().open(DB_NAME);
		  
		 // Path to the just created empty db
		 String outFileName = DB_PATH + DB_NAME;
		  
		 //Open the empty db as the output stream
		 OutputStream myOutput = new FileOutputStream(outFileName);
		  
		 //transfer bytes from the inputfile to the outputfile
		 byte[] buffer = new byte[1024];
		 int length;
		 while ((length = myInput.read(buffer))>0){
		 myOutput.write(buffer, 0, length);
		 }
		  
		 //Close the streams
		 myOutput.flush();
		 myOutput.close();
		 myInput.close();
		  
	}
		  
	public SQLiteDatabase openDataBase() throws SQLException{
	  
		 //Open the database
		 String myPath = DB_PATH + DB_NAME;
		 myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.CREATE_IF_NECESSARY);
		 return myDataBase;
	}
		  
	@Override
	public synchronized void close() {
	  
		 if(myDataBase != null)
			 myDataBase.close();
		  
		 super.close();
		  
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub
		
	}
}
	
	
